1. Technical Field
The disclosure relates in general to a semiconductor structure and a method for forming the same and more particularly to a MOS device and a method for forming the same.
2. Description of the Related Art
In the semiconductor technology, the feature size has been reduced. In the meantime, the rate, the efficiency, the density and the cost per integrated circuit unit have been improved. Recently, a power-saving IC is a trend for development for a semiconductor structure. The power-saving IC usually uses a LDMOS or an EDMOS as a switch.
For example, a method for increasing a breakdown voltage (BVdss) of a semiconductor structure such as a LDMOS or an EDMOS is decreasing a dopant concentration of a drain region and increasing a drift length. However, a specific on-state resistance (Ron, sp) of the semiconductor structure is increased due to the method. Therefore, the BVdss and the Ron, sp can not be improved at the same time.